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Add test of const item mutation with Drop impl

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David Tolnay 2020-09-26 18:42:19 -07:00
parent bb760b53bf
commit 0f6284c88d
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GPG key ID: F9BA143B95FF6D82
2 changed files with 24 additions and 12 deletions
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12
src/test/ui/lint/lint-const-item-mutation.rs
View file

@ -9,9 +9,19 @@ impl MyStruct {
fn use_mut(&mut self) {}
}
struct Mutable {
msg: &'static str,
}
impl Drop for Mutable {
fn drop(&mut self) {
println!("{}", self.msg);
}
}
const ARRAY: [u8; 1] = [25];
const MY_STRUCT: MyStruct = MyStruct { field: true, inner_array: ['a'], raw_ptr: 2 as *mut u8 };
const RAW_PTR: *mut u8 = 1 as *mut u8;
const MUTABLE: Mutable = Mutable { msg: "" };
fn main() {
ARRAY[0] = 5; //~ WARN attempting to modify
@ -29,4 +39,6 @@ fn main() {
*RAW_PTR = 0;
*MY_STRUCT.raw_ptr = 0;
}
MUTABLE.msg = "wow"; // no warning, because Drop observes the mutation
}

24
src/test/ui/lint/lint-const-item-mutation.stderr
View file

@ -1,5 +1,5 @@
warning: attempting to modify a `const` item
--> $DIR/lint-const-item-mutation.rs:17:5
--> $DIR/lint-const-item-mutation.rs:27:5
|
LL | ARRAY[0] = 5;
| ^^^^^^^^^^^^
@ -7,39 +7,39 @@ LL | ARRAY[0] = 5;
= note: `#[warn(const_item_mutation)]` on by default
= note: each usage of a `const` item creates a new temporary - the original `const` item will not be modified
note: `const` item defined here
--> $DIR/lint-const-item-mutation.rs:12:1
--> $DIR/lint-const-item-mutation.rs:21:1
|
LL | const ARRAY: [u8; 1] = [25];
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
warning: attempting to modify a `const` item
--> $DIR/lint-const-item-mutation.rs:18:5
--> $DIR/lint-const-item-mutation.rs:28:5
|
LL | MY_STRUCT.field = false;
| ^^^^^^^^^^^^^^^^^^^^^^^
|
= note: each usage of a `const` item creates a new temporary - the original `const` item will not be modified
note: `const` item defined here
--> $DIR/lint-const-item-mutation.rs:13:1
--> $DIR/lint-const-item-mutation.rs:22:1
|
LL | const MY_STRUCT: MyStruct = MyStruct { field: true, inner_array: ['a'], raw_ptr: 2 as *mut u8 };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
warning: attempting to modify a `const` item
--> $DIR/lint-const-item-mutation.rs:19:5
--> $DIR/lint-const-item-mutation.rs:29:5
|
LL | MY_STRUCT.inner_array[0] = 'b';
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: each usage of a `const` item creates a new temporary - the original `const` item will not be modified
note: `const` item defined here
--> $DIR/lint-const-item-mutation.rs:13:1
--> $DIR/lint-const-item-mutation.rs:22:1
|
LL | const MY_STRUCT: MyStruct = MyStruct { field: true, inner_array: ['a'], raw_ptr: 2 as *mut u8 };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
warning: taking a mutable reference to a `const` item
--> $DIR/lint-const-item-mutation.rs:20:5
--> $DIR/lint-const-item-mutation.rs:30:5
|
LL | MY_STRUCT.use_mut();
| ^^^^^^^^^^^^^^^^^^^
@ -52,13 +52,13 @@ note: mutable reference created due to call to this method
LL | fn use_mut(&mut self) {}
| ^^^^^^^^^^^^^^^^^^^^^
note: `const` item defined here
--> $DIR/lint-const-item-mutation.rs:13:1
--> $DIR/lint-const-item-mutation.rs:22:1
|
LL | const MY_STRUCT: MyStruct = MyStruct { field: true, inner_array: ['a'], raw_ptr: 2 as *mut u8 };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
warning: taking a mutable reference to a `const` item
--> $DIR/lint-const-item-mutation.rs:21:5
--> $DIR/lint-const-item-mutation.rs:31:5
|
LL | &mut MY_STRUCT;
| ^^^^^^^^^^^^^^
@ -66,13 +66,13 @@ LL | &mut MY_STRUCT;
= note: each usage of a `const` item creates a new temporary
= note: the mutable reference will refer to this temporary, not the original `const` item
note: `const` item defined here
--> $DIR/lint-const-item-mutation.rs:13:1
--> $DIR/lint-const-item-mutation.rs:22:1
|
LL | const MY_STRUCT: MyStruct = MyStruct { field: true, inner_array: ['a'], raw_ptr: 2 as *mut u8 };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
warning: taking a mutable reference to a `const` item
--> $DIR/lint-const-item-mutation.rs:22:5
--> $DIR/lint-const-item-mutation.rs:32:5
|
LL | (&mut MY_STRUCT).use_mut();
| ^^^^^^^^^^^^^^^^
@ -80,7 +80,7 @@ LL | (&mut MY_STRUCT).use_mut();
= note: each usage of a `const` item creates a new temporary
= note: the mutable reference will refer to this temporary, not the original `const` item
note: `const` item defined here
--> $DIR/lint-const-item-mutation.rs:13:1
--> $DIR/lint-const-item-mutation.rs:22:1
|
LL | const MY_STRUCT: MyStruct = MyStruct { field: true, inner_array: ['a'], raw_ptr: 2 as *mut u8 };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^